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Diabetes, depression share causes, mutual influences
The bidirectional connection between diabetes and mental health and, more specifically, the neuroendocrine link between diabetes and depression have become an important area of research in the medical community.
Endocrine Today spoke with Sherita Hill Golden, MD, MHS, Hugh P. McCormick family professor of endocrinology and metabolism and executive vice chair of the department of medicine at the Welch Center for Prevention, Epidemiology and Clinical Research at Johns Hopkins University School of Medicine, about reasons for the common occurrence of depression in individuals with type 2 diabetes, shared risk factors between the two, recommended health care models for management and measures to prevent this co-occurrence.
Why do diabetes and depression often occur in the same individuals? What do researchers predict to be the link between the two?
Golden: Individuals with diabetes are twice as likely to suffer from depression as individuals who do not have diabetes. Approximately 10% to 15% of individuals with diabetes have a diagnosed depressive disorder.
There are several theories for why the connection, but we believe that both depression and diabetes may arise from shared risk factors for both disorders that impact biological systems that lead to both depression and diabetes. An adverse intrauterine environment (eg, fetal malnutrition, maternal stress) and/or adverse external environment (eg, childhood adversity, poverty) may lead to poor health behaviors that promote obesity. Both obesity as well as the environmental exposures alter biological systems, including the hypothalamic-pituitary-adrenal axis — the body’s stress response system, the inflammatory axis and circadian/sleep rhythms, leading to insulin resistance and affective disturbances through alterations in brain plasticity.
Q: Is one more likely to precede the other? How does depression lead to diabetes and vice versa?
Golden: We now understand that the association between depression and diabetes is bidirectional. Depression is a risk factor for future development of type 2 diabetes and having type 2 diabetes is a risk factor for developing depression.
Depression can lead to type 2 diabetes through obesity-promoting health behaviors. Individuals with depression are less likely to exercise and adhere to a healthy diet and are more likely to smoke, which are risk factors for type 2 diabetes. They are also more likely to have higher levels of inflammation and alterations in the hypothalamic-pituitary-adrenal axis, which lead to insulin resistance. Finally, certain medications used to treat depression can lead to weight gain and obesity, increasing the risk for type 2 diabetes.
Diabetes can lead to depression due to psychological stress induced by the management of diabetes, which is worsened in the setting of having disabling diabetes complications. In addition, hyperglycemia has a negative effect on areas of the brain that control mood and cognition.
What do you recommend as the best care model to treat people with diabetes and depression?
Golden: An evidence-based collaborative care model that has effectively improved depressive symptoms and lowered HbA1c, blood pressure and lipids is the TEAMcare model developed by Wayne Katon, MD, a psychiatrist at the University of Washington, and colleagues through the Group Health Cooperative in Washington. To more effectively care for patients with both conditions, we need to implement collaborative care models that incorporate psychiatry/psychology and endocrinology into primary care.
What preventive measures can patients and providers take to stop the development of depression when someone already has diabetes or the development of diabetes in individuals with depression?
Golden: Awareness about the link between the two is an important initial step. Patients with diabetes should be routinely screened for depressive symptoms during the clinic visits. This can be done easily with the Patient Health Questionnaire-2. Patients who score at least 3 on this questionnaire have a 75% likelihood of having a depressive disorder and should be referred to treatment early. Good glycemic control to prevent development of complications and maintain quality of life is also key.
Patients with depression should be screened for diabetes, and they should be encouraged to exercise. Cognitive behavioral therapy, a crucial component of depression treatment, includes behavioral activation and physical activity, which is a key diabetes prevention measure.
What further research needs to be done in this area?
Golden: We still need to understand the biological mechanisms linking the two disorders to determine if there are shared intervention targets for further therapies that might prevent both type 2 diabetes and depression. – by Melissa J. Webb
For more information:
Sherita Hill Golden, MD, MHS, can be reached at sahill@jhmi.edu.
Disclosure: Golden reports no relevant financial disclosures.